It sounds like a bad dream — a really bad dream — but in a matter of days or at most weeks the Environmental Protection Agency (EPA) could become our national zoning board. Some say that, with the passing of Justice Antonin Scalia, the chances just became much bigger.

The reason is that the Supreme Court is about to decide whether to give the environmental agency the authority to make land use decisions throughout the nation. The court will not even have to hear arguments in American Farm Bureau Federation v. EPA to do this. It will only have to decide not to hear the appeal of a Third Circuit decision.

You don’t have to be a legal expert to have heard of the EPA’s Waters of the United States (WOTUS) regulation, stayed by the Sixth Circuit in October. As one newspaper put it, WOTUS empowers regulators to “micromanage any creek, pond or prairie pothole” and the land around them. In American Farm Bureau Federation v. EPA, the 3rd Circuit gave EPA the go-ahead to impose even farther-reaching control.

In an executive order signed weeks after taking office. President Obama instructed the environmental agency to “make full use of its powers” to lower the levels of phosphorus, nitrogen, and sediment in rainwater runoff, groundwater movement, and tributaries that reach the East Coast’s Chesapeake Bay. He added that this was to be done in a manner that “can be replicated” nationally. The goal was an EPA blueprint for watersheds covering the entire American landmass — from East Coast to West, including Alaska and Hawaii. But this “blueprint” wasn’t so much about improving the environment as grabbing more power to Washington.

EPA divided the 64,000-square-mile Chesapeake watershed (which covers the four states bordering the Chesapeake Bay as well as the District of Columbia and parts of New York and West Virginia) into thousands of sub-sections and categories. In each subsection, the agency-imposed limits on nutrient and sediment run off for several specific uses of land (agriculture, forests, urban runoff, and others). States were barred from adjusting mandated levels in one sub-section in light of greater progress, or greater difficulty, in another. EPA was rigid about its prescribed methods, too — requiring expensive buffer zones around fields and fencing off streams, for example. In effect, the regulation gives EPA the power to determine exactly how landowners can — and cannot — use their land. Whatever happened to private property rights.

Myopic rigidity, typical of federal regulators and particularly EPA, has human costs. In lower court filings, Pendleton County, West Virginia, reported that “a significant amount of farmland will have to be removed from production” as a result. Pendleton, the court document noted, is a poor county where families “displaced from farming would have little to no opportunity to replace their loss.

Even if you put the environment before everything else, those human costs are far from necessary. In 2013, at the request of the U.S. Department of Agriculture, a team from Penn State University analyzed comparative costs of EPA’s Chesapeake agriculture rule versus equally effective alternatives. In Virginia the potential savings from alternatives were 27 percent. In Pennsylvania they were 73 percent. In Delaware, Maryland, New York and West Virginia, they ranged from 82 percent to 86 percent.

EPA will inevitably apply federal land use “blueprints” to all watersheds nationwide. The Mississippi Basin, for example, covers all or part of 31 states. Producing 92 percent of the nation’s agricultural exports, it, too, releases large volumes of nitrogen, phosphorus, and sediment, into the watershed, and is the obvious next target.

The Supreme Court is the last line of defense. The president’s order and the EPA regulation were clearly contrary to the law. Under the Clean Water Act, the states, not the EPA, regulate agricultural runoff. Even when they set water quality goals with federal approval, the states retain broad authority over how to meet those goals. For example, the governor of Iowa recently announced a 30-year, $4.7 billion program to reduce substances sediment and nutrients in his state’s farm runoff. The Chesapeake rule washes away that legally required state role and, through it, state and local zoning powers, too.

The irony is that the states of the Chesapeake region were moving aggressively and effectively to clean their water before the EPA takeover. According to a 2014 report from the Chesapeake Bay Foundation, an environmental advocacy group, the Bay’s water quality had improved 40 percent since the early 1980s. By 2014, due largely to state-led efforts that pre-dated the EPA blueprint, the Bay’s water quality had returned to the levels not seen since the 1940s. The states are perfectly capable and determined to continue this progress without costly and inefficient EPA micromanagement.